I keep my tank on a chest of drawers which is just under 3ft. I'm collecting a new 3ft tank on monday and it will overhang the unit by 2 inches eaither side.
guess it should not be a problem, juwel sell a few stands that are smaller in length than the tank. but juwel do have a floating bottom , so this could be why. if the sides of the tank rest on the bottom glass, this is said to be a solid bottom tank, a floating bottom has the opposite construction.